24 行
719 B
C++
24 行
719 B
C++
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#include "PortRead_MCP23S17.h"
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/*
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PortRead_MCP23S17::begin() is not needed because port direction is already configured to input by default.
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SPI bus is configured in PortWrite_MCP23S17::begin().
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*/
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/*
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returns port value
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*/
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uint8_t PortRead_MCP23S17::read()
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{
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uint8_t portState; //bit wise
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//slower clock
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digitalWrite(SS, LOW); //enable Slave Select
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SPI.transfer(port.ADDR << 1 | 1); //read command
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SPI.transfer(port.num + 0x12); //register address to read data from
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portState = SPI.transfer(0); //save the data (0 is dummy data to send)
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digitalWrite(SS, HIGH); //disable Slave Select
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return portState;
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}
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